As a conventional typical wire gripper used when a wire, an electrical wire, a cable or the like is wire-tensioned, for example, there is one shown in FIG. 5 of Patent Document 1. The wire gripper grips a covered electrical wire 6 between a reception metal 3 provided in a wire gripper main body 1 and a pushing metal 5 attached to a swinging lever 2. When a handle 4 is operated, the swinging lever 2 is swung so that the pushing metal 5 is moved toward the reception metal 3.